LOS ANGELES — Robert Wagner has declined to be interviewed by detectives in a renewed inquiry into the drowning death of his wife Natalie Wood three decades ago, an investigator said Thursday.

Wagner was interviewed by authorities soon after Wood's drowning in 1981, but the actor is the only person who was on the yacht the night Wood died who has not spoken to detectives as part of the latest inquiry, despite repeated requests and attempts, sheriff's Lt. John Corina said.

Blair Berk, an attorney for Wagner and his family, said the actor had cooperated with authorities since his wife died.

Detectives began re-investigating the case in November 2011. Since then investigators have interviewed more than 100 people, but Wagner has refused and Corina said the actor's representatives have not given any reason for his silence.

The detective's remarks provided new insight into the case that has remained one of Hollywood's enduring mysteries. Earlier this week, coroner's officials released an updated autopsy report that had been under a security hold. It detailed why Wood's death had been reclassified from an accidental drowning to a drowning caused by "undetermined factors."

"Mr. Wagner has fully cooperated over the last 30 years in the investigation of the accidental drowning of his wife in 1981," Berk said in a prepared statement. "Mr. Wagner has been interviewed on multiple occasions by the Los Angeles sheriff's department and answered every single question asked of him by detectives during those interviews."

After 30 years, Berk said, neither Wagner nor his daughters have any new information to add. She said the latest investigation was prompted by people seeking to exploit and sensationalize the 30th anniversary of the death.

The renewed inquiry came after the yacht's captain Dennis Davern told "48 Hours" and the "Today" show that he heard Wagner and Wood arguing the night of her disappearance and believed Wagner was to blame for her death.

Authorities have not identified any suspects in the case.

Wood, 43, was on a yacht with Wagner, Christopher Walken and the boat captain on Thanksgiving weekend of 1981 before she somehow ended up in the water.

Corina said Walken gave a prepared statement and spoke to detectives for an hour.

Detectives have also interviewed other actors who knew both Wagner and Wood to learn more about their relationship.

Corina said detectives have tried at least 10 times to interview Wagner but have been refused. He said some of the refusals have come from the actor's attorney, and that detectives at one point traveled to Colorado to try to speak with Wagner but were unsuccessful.

Corina said the latest inquiry had turned up new evidence.

"Most of the people we've talked to were never talked to 30 years ago," he said. "We've got a lot of new information."

Asked if the information might lead to criminal charges, Corina said that would be up to prosecutors if they are presented a case.

"All we can do is collect the facts," he said. "We're still trying to collect all the facts."

Corina said new people have emerged with information each time the case is in the news. Detectives would like to interview other people who haven't agreed to talk, he said.

Coroner's officials released an update autopsy report on Monday that detailed the reasons Wood's death certificate was changed last year from a drowning death to "drowning and other undetermined factors."

The updated report states the change was made in part because investigators couldn't rule out that some of the bruises and marks on Wood's body happened before she went into the water.

"Since there are unanswered questions and limited additional evidence available for evaluation, it is opined by this medical examiner that the manner of death should be left as undetermined," Chief Medical Examiner Dr. Lakshmanan Sathyavagiswaran wrote in the report completed in June.

Officials also considered that Wood wasn't wearing a life jacket, had no history of suicide attempts and didn't leave a note as reasons to amend the death certificate.

Wood was famous for roles in films such as "West Side Story" and "Rebel Without a Cause" and was nominated for three Academy Awards.

Conflicting versions of what happened on the yacht have contributed to the mystery of her death. Wood, Wagner and Walken had all been drinking heavily in the hours before the actress disappeared.

Wagner wrote in a 2008 memoir that he and Walken argued that night. He wrote that Walken went to bed and he stayed up for a while, but when he went to bed, he noticed that his wife and a dinghy that had been attached to the yacht were missing.

"Nobody knows," he wrote. "There are only two possibilities; either she was trying to get away from the argument, or she was trying to tie the dinghy. But the bottom line is that nobody knows exactly what happened."